Air intake apparatus for internal combustion engine

ABSTRACT

An air intake apparatus for an internal combustion engine, the air intake apparatus includes: an air intake apparatus main body portion introducing air into a cylinder; a port portion provided integrally with a downstream side end portion of the air intake apparatus main body portion and inserted into an air intake port in a cylinder head; an air intake passage formed inside the air intake apparatus main body portion and the port portion, and through which an air-fuel mixture containing air and fuel flows; an injector provided in the air intake apparatus main body portion and introducing the fuel into the air intake passage; and a heater heating the fuel introduced by the injector. The injector is disposed at a position where the fuel is capable of being injected into the heater.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority under 35 U.S.C. § 119to Japanese Patent Application 2019-016675, filed on Feb. 1, 2019, theentire contents of which are incorporated herein by reference.

TECHNICAL FIELD

This disclosure relates to an air intake apparatus for an internalcombustion engine and, more particularly, to an air intake apparatus foran internal combustion engine provided with a heater.

BACKGROUND DISCUSSION

In the related art, an air intake apparatus for an internal combustionengine provided with a heater is known (see, for example, JP 5-29784B(Reference 1)).

An air intake apparatus for an internal combustion engine provided witha positive temperature coefficient (PTC) tablet (heater) is disclosed inReference 1. The air intake apparatus for an internal combustion enginedisclosed in Reference 1 is provided with an air intake pipe, a plate, acylindrical surface, and a fuel injector (injector).

The plate of Reference 1 is disposed between the downstream side endsurface of the air intake pipe and the outer surface of a cylinder headaround an opening in the upstream side end portion of the cylinder headin an intake flow direction. The cylindrical surface of Reference 1projects along the intake flow direction from the downstream side endportion of the plate in the intake flow direction into an air intakepassage of the cylinder head. The fuel injector of Reference 1 isdisposed at the downstream side part of the air intake pipe in theintake flow direction. The PTC heater of Reference 1 is disposed outsidethe cylindrical surface in a direction orthogonal to the intake flowdirection.

In the air intake apparatus for an internal combustion engine disclosedin Reference 1, fuel vaporization is promoted by the fuel that has beeninjected from the fuel injector toward the inner surface of thecylindrical surface being heated by the PTC heater.

However, the air intake apparatus for an internal combustion enginedisclosed in Reference 1 is inconvenient in that the fuel injected fromthe fuel injector intrudes between the plate and the downstream side endsurface of the air intake pipe and between the plate and the outersurface of the cylinder head around the opening in the upstream side endportion of the cylinder head. Accordingly, the air intake apparatus foran internal combustion engine disclosed in Reference 1 has problems inthat no fuel vaporization by the PTC heater (heater) can be promoted andno sufficient sealability can be ensured with respect to the fuelinjected from the fuel injector (injector).

Thus, a need exists for an air intake apparatus for an internalcombustion engine which is not susceptible to the drawback mentionedabove.

SUMMARY

An air intake apparatus for an internal combustion engine according toan aspect of this disclosure includes an air intake apparatus main bodyportion introducing air into a cylinder, a port portion providedintegrally with a downstream side end portion of the air intakeapparatus main body portion and inserted into an air intake port in acylinder head, an air intake passage formed inside the air intakeapparatus main body portion and the port portion, and through which anair-fuel mixture containing air and fuel flows, an injector provided inthe air intake apparatus main body portion and introducing fuel into theair intake passage, and a heater heating the fuel introduced by theinjector. The injector is disposed at a position where the fuel iscapable of being injected into the heater.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and additional features and characteristics of thisdisclosure will become more apparent from the following detaileddescription considered with the reference to the accompanying drawings,wherein:

FIG. 1 is a cross-sectional view illustrating a state where an intakemanifold according to the present embodiment is attached to a cylinderhead;

FIG. 2 is a perspective cross-sectional view of the downstream side partof the intake manifold according to the present embodiment;

FIG. 3 is a perspective view of the intake manifold according to thepresent embodiment as viewed from the upstream side in an intake flowdirection;

FIG. 4 is a perspective view of the intake manifold according to thepresent embodiment as viewed from the Z1 direction side;

FIG. 5 is a cross-sectional view taken along line V-V in FIG. 1;

FIG. 6A is a front view of a seal member;

FIG. 6B is a cross-sectional view taken along line VIB-VIB in FIG. 6A;

FIG. 7 is a schematic diagram illustrating a cross section taken alongline VII-VII in FIG. 5, a temperature sensor, and a control portion;

FIG. 8 is a flowchart illustrating the heater heating treatment at atime of the initial operation of an engine that is performed in thecontrol portion of the engine provided with the intake manifoldaccording to the present embodiment;

FIG. 9 is a flowchart illustrating the heater heating treatment at atime of the restart of the engine that is performed in the controlportion of the engine provided with the intake manifold according to thepresent embodiment;

FIG. 10 is a cross-sectional view of a port portion according to a firstmodification example of the present embodiment and corresponds to across-sectional view taken along line X-X in FIG. 5; and

FIG. 11 is a cross-sectional view of a port portion according to asecond modification example of the present embodiment and corresponds toa cross-sectional view taken along line XI-XI in FIG. 5.

DETAILED DESCRIPTION

Hereinafter, an embodiment disclosed here will be described withreference to the drawings.

As illustrated in FIG. 1, an automotive engine E (an example of the“internal combustion engine” in the claims) is provided with a cylinderblock 1, a cylinder head 2, and an intake manifold 3 (an example of the“air intake apparatus for an internal combustion engine” in the claims).

The engine E has a structure in which the cylinder head 2 is fixed onthe Z1 direction side of the cylinder block 1. The cylinder head 2 has aplurality of air intake ports 21 and a plurality of exhaust ports (notillustrated) communicating with a combustion chamber 22. In addition,the cylinder head 2 is provided with an intake valve 13 and an exhaustvalve (not illustrated) opening/closing an opening allowing thecombustion chamber 22 and each of the plurality of air intake ports 21and the plurality of exhaust ports to communicate with each other.

In the present embodiment, upstream and downstream are defined on thebasis of the flow of the air flow that flows through the air intake port21 and is suctioned into the combustion chamber 22 (hereinafter, intakeflow direction A). In addition, the direction of extension of a cylinder4 is defined as the Z direction (vertical direction), one direction inthe Z direction is defined as the Z1 direction (upward direction), andthe other direction in the Z direction is defined as the Z2 direction(downward direction) in a state where the engine E having a plurality ofthe cylinders 4 (only one being illustrated in FIG. 1) is mounted in avehicle (not illustrated). The direction in which the plurality ofcylinders 4 are arranged is defined as the X direction (forward-rearwarddirection), one direction in the X direction is defined as the X1direction (forward direction), and the other direction in the Xdirection is defined as the X2 direction (rearward direction). Thedirection that is orthogonal to the Z direction and the X direction isdefined as the Y direction (leftward-rightward direction), one directionin the Y direction is defined as the Y1 direction (rightward direction),and the other direction in the Y direction is defined as the Y2direction (leftward direction).

The air intake port 21 is provided at a position between an opening 23on the upstream side in the intake flow direction A and an air intakeport 24 on the downstream side in the intake flow direction A. The airintake port 24 allows the air intake port 21 and the combustion chamber22 to communicate with each other. The air intake port 21 is inclined inthe Z2 direction as the air intake port 21 goes in the Y1 direction. Theair intake port 21 includes an enlarged portion 21 a, a stepped portion21 b, and a reduced portion 21 c. At the air intake port 21, theenlarged portion 21 a, the stepped portion 21 b, and the reduced portion21 c are provided in this order from the upstream side in the intakeflow direction A.

A through hole extending along the intake flow direction A constitutesthe enlarged portion 21 a. The enlarged portion 21 a is provided in asubstantially rectangular shape (see FIG. 5) when viewed from theupstream side in the intake flow direction A. In the intake flowdirection A, the enlarged portion 21 a is provided up to the middle partof the air intake port 21. In the direction that is orthogonal to theintake flow direction A, the enlarged portion 21 a is larger in lengththan the reduced portion 21 c. In the intake flow direction A, themaximum length of the enlarged portion 21 a is smaller than the maximumlength of the reduced portion 21 c.

The stepped portion 21 b interconnects the enlarged portion 21 a and thereduced portion 21 c in the intake flow direction A. In other words, inthe intake flow direction A, the upstream side end portion of thestepped portion 21 b is provided integrally with the downstream side endportion of the enlarged portion 21 a. In the intake flow direction A,the downstream side end portion of the stepped portion 21 b is providedintegrally with the upstream side end portion of the reduced portion 21c. The stepped portion 21 b has a tapered shape in which the downstreamside in the intake flow direction A becomes narrow. In other words, thestepped portion 21 b is inclined to the middle portion side (inner side)of the air intake port 21 in the direction that is orthogonal to theintake flow direction A as the stepped portion 21 b goes in the intakeflow direction A.

A through hole extending along the intake flow direction A constitutesthe reduced portion 21 c. The reduced portion 21 c is provided in arectangular shape (see FIG. 5) when viewed from the upstream side in theintake flow direction A. In the intake flow direction A, the reducedportion 21 c is provided from the middle part of the air intake port 21to the downstream side end portion of the air intake port 21.

Intake Manifold

As illustrated in FIG. 1, the engine E is configured to supply anair-fuel mixture M containing air K and fuel F into the combustionchamber 22 of the cylinder 4 by means of the intake manifold 3.Specifically, the intake manifold 3 includes an injector 31, an airintake apparatus main body portion 32, a port portion 33, a gasket 34(an example of the “seal member” in the claims), an air intake passage35, an embedded recessed portion 36, a heater 37, a heat insulatingmember 38 (see FIG. 5), and a heater protection film 39.

Injector

The injector 31 is configured to inject the fuel F in the form of foginto the air K flowing toward the combustion chamber 22. The injector 31is provided in the air intake apparatus main body portion 32 and isconfigured to introduce the fuel F into the air intake passage 35.

Specifically, the injector 31 injects the fuel F such that the fuel Fdiffuses to the periphery as the fuel F goes toward the combustionchamber 22 in the intake flow direction A. Here, the injector 31diffuses the fuel F in the form of an injection region 6. In otherwords, the injection region 6 expands in the direction that isorthogonal to (intersects with) the injection direction of the fuel F asthe injection region 6 goes downstream in the injection direction of thefuel F.

In addition, the injector 31 is inclined to the Z1 direction (upwarddirection) side with respect to the direction in which the air intakeport 21 extends. In other words, the injector 31 is inclined by apredetermined angle θ with respect to the direction in which the airintake port 21 extends.

The predetermined angle θ of the injector 31 is an angle at which atleast a part of the heater 37 can be disposed within the range of thedownstream end of the injection region 6. Further, the predeterminedangle θ of the injector 31 is an angle at which a part of the air intakeport 24 can be disposed within the range of the downstream end of theinjection region 6. The part of the heater 37 indicates a part of thesurface of the heater 37 that is on the air intake passage 35 side inthe direction orthogonal to the intake flow direction A. In addition,the part of the air intake port 24 indicates the part between the middleposition of the air intake port 24 and the end portion of the air intakeport 24 that is on the intake manifold 3 side in the directionorthogonal to the intake flow direction A.

The injector 31 is disposed at a position where the fuel F can beinjected into the heater 37. In other words, the injector 31 is disposedon the downstream side of the air intake apparatus main body portion 32in the intake flow direction A in a state of being inclined by thepredetermined angle θ. Here, a distal end portion 31 a of the injector31 is disposed upstream of a boundary part D (described later) betweenthe air intake apparatus main body portion 32 and the port portion 33 inthe intake flow direction A. Specifically, in the intake flow directionA, the distal end portion 31 a of the injector 31 is disposed upstreamof an outer surface 2 a of the cylinder head 2 around the opening 23 ofthe air intake port 21. In other words, in the intake flow direction A,the distal end portion 31 a of the injector 31 is disposed upstream ofthe gasket 34.

A part of the distal end portion 31 a of the injector 31 is disposed inthe air intake passage 35. Specifically, the part of the distal endportion 31 a of the injector 31 that is on the cylinder block 1 side isdisposed in the air intake passage 35 in the direction orthogonal to theintake flow direction A.

The fuel F is, for example, gasoline, gas fuel, or ethanol. In thismanner, the engine E is a port injection engine in which the fuel F isinjected into the air intake port 21.

Air Intake Apparatus Main Body Portion and Port Portion

As illustrated in FIGS. 1 to 4, the air intake apparatus main bodyportion 32 and the port portion 33 are provided in each of the pluralityof air intake ports 21 respectively supplying the air-fuel mixture M tothe plurality of cylinders 4 in the engine E. Accordingly, only theconfigurations of the air intake apparatus main body portion 32 and theport portion 33 that are disposed in the X2 direction side end portionamong the plurality of cylinders 4 will be described below. Likewise,only those disposed in the X2 direction side end portion will bedescribed with regard to the gasket 34, the air intake passage 35, theembedded recessed portion 36, the heater 37, the heat insulating member38 (see FIG. 5), and the heater protection film 39.

As illustrated in FIG. 1, the air intake apparatus main body portion 32is configured to introduce the air K into the combustion chamber 22.

Specifically, the air intake apparatus main body portion 32 is formed ofresin. The air intake apparatus main body portion 32 has a surge tank(not illustrated), an air intake pipe portion 32 a, a flange portion 32b, an injector attaching portion 32 c, and a recessed portion 32 d.

The surge tank temporarily stores the air K. The surge tank is disposedin the upstream side end portion in the intake flow direction A in theintake manifold 3. The air intake pipe portion 32 a allows the air K toflow along the passage that is formed in the air intake pipe portion 32a. The air intake pipe portion 32 a is disposed downstream of the surgetank. The air intake pipe portion 32 a interconnects the surge tank andthe flange portion 32 b.

The flange portion 32 b is provided for inserting a fastener (notillustrated) fixing the intake manifold 3 to the cylinder head 2. Theintake manifold 3 is fixed to the cylinder head 2 via the flange portion32 b.

The flange portion 32 b has a flange shape. The flange portion 32 b isdisposed so as to face the outer surface 2 a of the cylinder head 2 andis provided integrally with the end portion of the port portion 33 thatis on the air intake apparatus main body portion 32 side. In otherwords, the flange portion 32 b has a facing surface 132 facing the outersurface 2 a of the cylinder head 2. In the direction orthogonal to theintake flow direction A, the inner side end portion of the facingsurface 132 is integrally connected to the port portion 33.

As illustrated in FIGS. 1 and 2, the injector attaching portion 32 c isprovided so that the injector 31 is attached to the air intake apparatusmain body portion 32. The injector attaching portion 32 c has a spaceinto which the injector 31 is inserted. The space of the injectorattaching portion 32 c extends in a direction inclined by thepredetermined angle θ with respect to the direction of extension of theair intake port 21 so that the injector 31 is inclined by thepredetermined angle θ and attached to the air intake apparatus main bodyportion 32.

The injector attaching portion 32 c is provided at the Z1 direction side(upper side) part of the air intake apparatus main body portion 32. Theinjector attaching portion 32 c is provided in the downstream side endportion of the air intake apparatus main body portion 32 in the intakeflow direction A. In other words, the injector attaching portion 32 c isprovided from the downstream side part of the air intake pipe portion 32a to the downstream side end portion of the flange portion 32 b in theintake flow direction A. The injector attaching portion 32 c projects inthe direction inclined by the predetermined angle θ from the Z1direction side (upper side) part of the air intake apparatus main bodyportion 32.

As illustrated in FIGS. 1 and 3, the recessed portion 32 d is configuredsuch that the gasket 34 is fitted. Specifically, the recessed portion 32d is the end surface of the flange portion 32 b on the downstream sidein the intake flow direction A that is recessed in the directionopposite to the intake flow direction A. The recessed portion 32 d isformed in a circumferential shape so as to surround the upstream sideend portion of the port portion 33 in the intake flow direction A.

As illustrated in FIG. 1, the port portion 33 constitutes a heatinsulating port structure insulating heat from the cylinder head 2. Inother words, the port portion 33 has the shape of a resin tubesuppressing heat transfer from the cylinder head 2 with respect to theair K supplied from the intake manifold 3 to the combustion chamber 22.The port portion 33 is a tubular part inserted into the air intake port21 from the opening 23 on the upstream side of the air intake port 21.

The port portion 33 is configured to have heat resistance against heattransferred from the cylinder head 2 and heat from the combustionchamber 22. Specifically, the port portion 33 is formed of a non-foamedresin material. For example, the port portion 33 is formed of aheat-resistant polyamide 6. As a result, it is possible to suppress achange in physical properties (such as dissolution) with respect to heattransferred from the cylinder head 2 and heat from the combustionchamber 22 in the range where the port portion 33 is disposed.

The port portion 33 of the present embodiment is integrally provided inthe downstream side end portion of the air intake apparatus main bodyportion 32 and is inserted in the air intake port 21 in the cylinderhead 2. In other words, in the intake flow direction A, the upstreamside end portion of the port portion 33 and the downstream side end ofthe air intake apparatus main body portion 32 are integrally provided.Specifically, the port portion 33 integrally projects along the intakeflow direction A from the downstream side end portion of the air intakeapparatus main body portion 32 in the intake flow direction A(downstream side end portion of the flange portion 32 b). In addition,around the central axis line that extends in the intake flow directionA, the upstream side end portion of the port portion 33 and thedownstream side end of the air intake apparatus main body portion 32 areintegrally provided over the entire circumferential direction.

Here, the connection part between the upstream side end portion of theport portion 33 and the downstream side end of the air intake apparatusmain body portion 32 is the boundary part D. The boundary part D is alsoa contact part between the outer surface 2 a of the cylinder head 2 andthe facing surface 132 of the flange portion 32 b. In the Y direction, apart of the boundary part D is disposed outside the outer surface of thecylinder block 1. In other words, in the Y direction, the maximumdistance between the boundary part D and the combustion chamber 22 islarger than the distance between the outer surface of the cylinder block1 and the combustion chamber 22.

The port portion 33 faces an inner surface 21 d of the air intake port21. Specifically, the port portion 33 has a length at which insertion ispossible from the upstream side end portion of the air intake port 21 tothe vicinity of the middle position of the air intake port 21 in theintake flow direction A. In other words, in the intake flow direction A,the projecting distal end portion of the port portion 33 is disposed atthe upstream side part of the reduced portion 21 c of the air intakeport 21 (upstream side part between the middle position and thedownstream end position of the air intake port 21). Accordingly, theport portion 33 is disposed between the inner surface 21 d of the airintake port 21 and the air intake passage 35 from the upstream side endportion of the air intake port 21 to the upstream side part of thereduced portion 21 c of the air intake port 21. As a result, it ispossible to suppress heat transfer from the cylinder head 2 to the air Kflowing through the air intake passage 35 from the upstream side endportion of the air intake port 21 to the upstream side part of thereduced portion 21 c of the air intake port 21.

In the cross section in the intake flow direction A, the port portion 33has a shape along the inner surface 21 d of the air intake port 21. Inother words, in the cross section in the intake flow direction A, theport portion 33 has a shape along the enlarged portion 21 a and steppedportion 21 b parts of the inner surface 21 d of the air intake port 21.

Specifically, as illustrated in FIGS. 3 and 4, the port portion 33 has atapered shape extending along the intake flow direction A. In otherwords, the part of the port portion 33 that corresponds to the enlargedportion 21 a is provided in a straight line along the intake flowdirection A. The part of the port portion 33 that corresponds to thestepped portion 21 b has a tapered shape.

Specifically, at the part of the port portion 33 that corresponds to thestepped portion 21 b, each of the parts on both sides in the X directionis formed in a tapered shape. In other words, each of the parts on bothsides in the X direction at the part of the port portion 33 thatcorresponds to the stepped portion 21 b is inclined to the middleposition side of the air intake passage 35 in the Z direction as each ofthe parts goes in the intake flow direction A. Here, at the part of theport portion 33 that corresponds to the stepped portion 21 b, the partson both sides in the X direction are respectively disposed downstream ofthe parts on both sides in the Z direction in the intake flow directionA.

In addition, as illustrated in FIG. 5, an air insulation layer 5 isformed between an outer surface 33 b of the port portion 33 and theinner surface 21 d of the air intake port 21 in the direction orthogonalto the intake flow direction A. In other words, the air insulation layer5 is an air layer formed between the outer surface 33 b of the portportion 33 and the inner surface 21 d of the air intake port 21 in astate where the port portion 33 is inserted in the air intake port 21.Here, in the direction orthogonal to the intake flow direction A, thecross-sectional shape of the port portion 33 is formed so as to besmaller than the cross-sectional shape of the air intake port 21 so thatthe air insulation layer 5 is formed.

As illustrated in FIG. 1, the interval between the outer surface 33 b ofthe port portion 33 and the inner surface 21 d of the air intake port 21is substantially constant. In other words, in the direction orthogonalto the intake flow direction A, the interval between the outer surface33 b of the port portion 33 and the enlarged portion 21 a part of theinner surface 21 d of the air intake port 21 is substantially constant.In addition, in the direction orthogonal to the intake flow direction A,the interval between the outer surface 33 b of the port portion 33 andthe stepped portion 21 b part of the inner surface 21 d of the airintake port 21 is substantially constant. In this manner, the outersurface 33 b of the port portion 33 is disposed at a position offset tothe inner side in the direction orthogonal to the intake flow directionA.

In addition, the port portion 33 is configured such that the air Ksmoothly flows out into the air intake port 21. Specifically, an innersurface 33 a of the port portion 33 is provided so as to besubstantially flush with the inner surface 21 d of the air intake port21 in the intake flow direction A.

Gasket

The gasket 34 is configured to suppress intrusion of foreign matter suchas water into the air intake port 21. Specifically, the gasket 34 isformed of an elastic member. In other words, the gasket 34 is formed ofheat-resistant nitrile rubber, hydrogenated nitrile rubber, siliconerubber, fluororubber, and the like.

The gasket 34 is enhanced in terms of sealability by being pinched andcompressed between the flange portion 32 b of the air intake apparatusmain body portion 32 and the outer surface 2 a of the cylinder head 2.In other words, the gasket 34 is disposed between the flange portion 32b of the air intake apparatus main body portion 32 and the outer surface2 a of the cylinder head 2. Here, the gasket 34 is fitted in therecessed portion 32 d formed in the flange portion 32 b.

In addition, as illustrated in FIGS. 3 and 6A, the gasket 34 is providedso as to surround the upstream side end portion of the port portion 33in the intake flow direction A. The gasket 34 is formed in acircumferential shape. In other words, the gasket 34 has a shape alongthe circumferential direction around the central axis line extending inthe intake flow direction A. The gasket 34 has a substantiallyrectangular shape when viewed from the downstream side in the intakeflow direction A.

In addition, as illustrated in FIG. 6B, the cross-sectional shape of thegasket 34 has a substantially elliptical shape extending along theintake flow direction A in the direction that is along the intake flowdirection A. Specifically, the gasket 34 has a compression portion 34 aand a rib portion 34 b.

The compression portion 34 a is compressed by each of the flange portion32 b of the air intake apparatus main body portion 32 and the outersurface 2 a of the cylinder head 2. In the intake flow direction A, theupstream side end portion of the compression portion 34 a is in contactwith the downstream side end surface of the flange portion 32 b of theair intake apparatus main body portion 32. In the intake flow directionA, the downstream side end portion of the compression portion 34 a is incontact with the outer surface 2 a of the cylinder head 2.

The rib portion 34 b holds the posture of the gasket 34 fitted in therecessed portion 32 d. The rib portion 34 b is in contact with each ofthe pair of inner side surfaces of the recessed portion 32 d that faceeach other in the X direction. In other words, the rib portion 34 bprojects in the X1 direction from the side surface of the compressionportion 34 a that is on the X1 direction side. In addition, the ribportion 34 b projects in the X2 direction from the side surface of thecompression portion 34 a that is on the X2 direction side. In the intakeflow direction A, the rib portion 34 b is disposed at the middle part ofthe compression portion 34 a.

Air Intake Passage

As illustrated in FIG. 1, the air intake passage 35 is formed inside theair intake apparatus main body portion 32 and the port portion 33 and isconfigured so as to allow the air-fuel mixture M to flow. In otherwords, the air intake passage 35 is the internal space of the air intakeapparatus main body portion 32 and the port portion 33. Specifically,the air intake passage 35 passes through the air intake apparatus mainbody portion 32 and the port portion 33 in the intake flow direction A.The air intake passage 35 has a flat shape (see FIG. 5) in which the airintake passage 35 is shorter in the Z direction than in the X directionwhen viewed from the downstream side in the intake flow direction A.

Embedded Recessed Portion

The embedded recessed portion 36 is an inner surface 3 a of the intakemanifold 3 that is recessed in the direction orthogonal to the intakeflow direction A. Specifically, the embedded recessed portion 36 is theinner surface 33 a of the port portion 33 that is recessed to the outerside in the direction orthogonal to the intake flow direction A. Theembedded recessed portion 36 is disposed at the part of the port portion33 that corresponds to the injection region 6 of the fuel F injectedfrom the injector 31.

As illustrated in FIG. 5, in the direction orthogonal to the intake flowdirection A, the cross-sectional shape of the embedded recessed portion36 has a substantially U shape. In the direction orthogonal to theintake flow direction A, the embedded recessed portion 36 is formed inthe lower portion of the intake manifold 3 (at the part that is closerto the Z1 direction side than the middle part in the Z direction).

Here, the heater 37 is disposed in the embedded recessed portion 36. Inaddition, in the direction orthogonal to the intake flow direction A,the heat insulating member 38 is disposed outside the embedded recessedportion 36 and the heater 37 is stacked inside the heat insulatingmember 38. Specifically, a layered structure formed by the heaterprotection film 39, the heater 37, and the heat insulating member 38 isembedded in the embedded recessed portion 36.

Here, the heater protection film 39, the heater 37, and the heatinsulating member 38 are embedded in the embedded recessed portion 36 ina state where the heater protection film 39, the heater 37, and the heatinsulating member 38 are stacked in this order in the directionorthogonal to the intake flow direction A.

Heater

As illustrated in FIG. 7, the heater 37 is configured to heat the fuel Fintroduced by the injector 31. Specifically, the heater 37 is configuredto vaporize the fuel F that has adhered without vaporization to theinner surface 3 a of the intake manifold 3 when, for example, the engineis cold immediately after the start of the engine (before a three-waycatalyst disposed in an exhaust pipe is warmed up). As a result, theair-fuel ratio (A/F) at the time of a cold start is stabilized, theamount of fuel injection can be controlled so as to be small, and it ispossible to suppress an excessive amount of the fuel F being suppliedinto the combustion chamber 22.

Specifically, the heater 37 includes a heat generating element havinghigh temperature rise characteristics. In other words, it is preferablethat the heater 37 has the high temperature rise characteristics ofreaching a predetermined temperature (approximately 70° C.) within avery short time (approximately 3 seconds to approximately 5 seconds)from the time of the initial operation of the engine. Accordingly, theheater 37 has, for example, carbon graphite or a carbon nanotube as aheat generating element having carbon as a main component. Here, it ismore preferable that the heater 37 is formed by a sheet-shaped carbonnanotube being pasted to the heater protection film 39 or a liquidcarbon nanotube being applied to the heater protection film 39.

As illustrated in FIGS. 1 and 7, the heater 37 is disposed at a positionwhere heat can be directly applied to the fuel F that has adheredwithout vaporization to the inner surface 3 a of the intake manifold 3.In other words, at least a part of the heater 37 is disposed at the partof the port portion 33 that corresponds to the injection region 6 of thefuel F injected from the injector 31.

Specifically, the heater 37 is disposed in the port portion 33 in theintake flow direction A. Here, the heater 37 is disposed between thedistal end portion 31 a of the injector 31 and the downstream side endportion of the port portion 33 in the intake flow direction A. In otherwords, the heater 37 is provided in the vicinity of the distal endportion of the intake manifold 3.

As illustrated in FIGS. 1 and 5, the heater 37 is configured to reliablyapply heat to the fuel F that diffuses and adheres to the inner surface33 a of the port portion 33. Specifically, in the direction orthogonalto the intake flow direction A, the cross-sectional shape of the heater37 has a substantially U shape. In the direction orthogonal to theintake flow direction A, the heater 37 is formed in the lower portion ofthe intake manifold 3 (at the part that is closer to the Z1 directionside than the middle part in the Z direction). The heater 37 is a planarheater that is along the shape of the embedded recessed portion 36 inthe direction orthogonal to the intake flow direction A.

The heater 37 is provided on the inner surface 33 a side of the portportion 33. In other words, the heater 37 is disposed at a positionadjacent to the air intake passage 35 via the heater protection film 39in the direction orthogonal to the intake flow direction A.

Heat Insulating Member

As illustrated in FIG. 7, the heat insulating member 38 is configured tofunction as a heat insulating material suppressing heat transfer fromthe heater 37. Specifically, the heat insulating member 38 has a foamedresin material. In other words, the heat insulating member 38 is formedby foam molding being performed on a polyamide. In this manner, the heatinsulating member 38 is improved in terms of heat insulation performanceby air bubbles in which gas is sealed being formed. It is preferablethat the heat transfer coefficient of the heat insulating member 38 isapproximately 10% or less of the heat transfer coefficient of the heaterprotection film 39.

The heat insulating member 38 is disposed inside the intake manifold 3.Specifically, the heat insulating member 38 is embedded in the embeddedrecessed portion 36. Here, the heat insulating member 38 is provided ina state of being in direct contact with the inner surface 3 a of theintake manifold 3.

As illustrated in FIG. 5, the heat insulating member 38 has asubstantially U shape when viewed from the downstream side in the intakeflow direction A. In the direction orthogonal to the intake flowdirection A, the heater 37 is formed in the lower portion of the intakemanifold 3 (at the part that is closer to the Z1 direction side than themiddle part in the Z direction).

Heater Protection Film

The heater protection film 39 is configured to protect the heater 37 sothat the fuel F injected from the injector 31 does not adhere to theheater 37. Specifically, the heater protection film 39 covers the heater37 from the air intake passage 35 side. In other words, the heaterprotection film 39 is provided over the entire cross-sectional shape ofthe heater 37 that is orthogonal to the intake flow direction A. In thismanner, the heater protection film 39 is provided along the innersurface of the heater 37.

The heater protection film 39 is formed of a material that is easy tofit along the inner surface of the heater 37. Specifically, a resin filmconstitutes the heater protection film 39. Here, it is preferable thatthe heater protection film 39 is a resin material having heatresistance, oil resistance, and chemical resistance. For example,polyimide or the like is preferably used as the heater protection film39.

The heater protection film 39 is configured to easily transfer heat fromthe heater 37. Specifically, the heater protection film 39 is formed ofa thin resin film so as not to hinder heat radiation from the heater 37toward the air intake passage 35 side. In other words, it is preferablethat the heater protection film 39 is, for example, a thin resin filmhaving a thickness of approximately 0.125 [mm].

In addition, the heater protection film 39 is less heat-insulating thanthe heat insulating member 38. Specifically, it is preferable that theheat transfer coefficient of the heater protection film 39 isapproximately 10 times or more the heat transfer coefficient of the heatinsulating member 38.

Layered Structure

As illustrated in FIG. 7, a four-layer structure constitutes theinternal structure of the embedded recessed portion 36 part of theintake manifold 3. Specifically, the heater protection film 39, theheater 37, the heat insulating member 38, and the intake manifold 3 arestacked in this order in the direction orthogonal to the intake flowdirection A. In other words, a layered structure formed by the heaterprotection film 39, the heater 37, the heat insulating member 38, andthe intake manifold 3 is formed at a part of the intake manifold 3.

Specifically, the heat insulating member 38 is stacked outside theheater 37 in the direction orthogonal to the intake flow direction A andis configured to insulate heat from the heater 37. In other words, theheat insulating member 38 is in contact with the heater 37. The heaterprotection film 39 is stacked inside the heater 37 in the directionorthogonal to the intake flow direction A. In other words, the heaterprotection film 39 is in contact with the heater 37.

The intake manifold 3 is configured to enclose the peripheral edgeportion of the heat insulating member 38. In other words, the intakemanifold 3 is configured to thermally protect the heat insulating member38 by being more heat-resistant than the heat insulating member 38.

Specifically, the port portion 33 has a flange portion 33 c, whichprojects toward the center of a cross-sectional portion of the airintake passage 35, in the downstream side end portion of the portportion 33 in the intake flow direction A. In other words, the heatinsulating member 38 is covered with the flange portion 33 c from theside of the direction opposite to the intake flow direction A. Here, theflange portion 33 c forms the end portion of the embedded recessedportion 36 in the intake flow direction A. In this manner, the intakemanifold 3 thermally blocks the heat insulating member 38 from the highheat that is released from the combustion chamber 22 (see FIG. 1) bymeans of the flange portion 33 c.

In addition, the intake manifold 3 is configured to suppress peeling ofthe heater protection film 39 provided with the heater 37 from the heatinsulating member 38. Specifically, the port portion 33 has a projectingpressing portion 33 d pressing the heater protection film 39 providedwith the heater 37 from the direction orthogonal to the intake flowdirection A. The projecting pressing portion 33 d presses the peripheraledge portion of the surface of the heater protection film 39 providedwith the heater 37 that is on the air intake passage 35 side. In otherwords, the projecting pressing portion 33 d projects toward the centerof the embedded recessed portion 36 from the peripheral edge portion ofthe embedded recessed portion 36 that is on the intake flow direction Aside. The projecting pressing portion 33 d projects toward the center ofthe embedded recessed portion 36 from the peripheral edge portion of theembedded recessed portion 36 that is on the side opposite to the intakeflow direction A.

ECU

As illustrated in FIG. 7, the engine E is provided with a temperaturesensor 7 measuring the temperature of the heater 37 and a controlportion 8 controlling the temperature of the heater 37 on the basis ofthe temperature measured by the temperature sensor 7.

An engine control unit (ECU) including a central processing unit (CPU,not illustrated) as a control circuit and a memory (not illustrated) asa storage medium constitutes the control portion 8.

The control portion 8 controls each portion of the engine E by the CPUexecuting an engine control program stored in the memory. In addition,the control portion 8 is configured to grasp information such as a firstpredetermined condition, a second predetermined condition, and thetemperature of the heater 37.

Here, the first predetermined condition is a condition at a time whenthe heater 37 is preheated (residual heat) before the initial operationof the engine and is, for example, a condition including at least one ofa user approaching the vehicle with a wireless key, door unlocking bythe user, the user taking his or her seat, and brake pedal depression bythe user. In addition, the second predetermined condition is a conditionat a time when the heater 37 is preheated (residual heat) before theengine is restarted and is, for example, a condition including at leastone of the temperature of outside air, the temperature of the three-waycatalyst disposed in the exhaust pipe, the temperature of the inner wallsurface of the air intake port 21, and the temperature of the coolingwater of the engine E.

The control portion 8 is configured to prevent excessive heat generationof the heater 37 on the basis of the temperature measured by thetemperature sensor 7 and in accordance with the engine control program.In addition, the control portion 8 is configured to reliably vaporizethe fuel F that has adhered without vaporization to the inner surface 33a of the port portion 33 by means of the heater 37, on the basis of thefirst predetermined condition and the second predetermined condition,and in accordance with the engine control program.

An optimal sensor as the temperature sensor 7 is selected from athermistor, a thermocouple, a side temperature resistor, and the like.Preferably used as the temperature sensor 7 is a sensor having a quickresponse to a change in temperature.

Heater Heating Treatment at Time of Initial Engine Operation

The heater heating treatment at a time of the initial operation of theengine that is included in the engine control processing by the controlportion 8 will be described below with reference to FIG. 8. The heaterheating treatment at the time of the initial engine operation is toinitiate the heating of the heater 37 in advance before the initialengine operation.

In Step S1, the control portion 8 determines whether or not the firstpredetermined condition (such as the door unlocking by the user) hasbeen satisfied. The control portion 8 proceeds to Step S2 in a casewhere the first predetermined condition is satisfied and returns to StepS1 in a case where the first predetermined condition is not satisfied.In Step S2, the control portion 8 determines whether or not thetemperature of the three-way catalyst is a low temperature lower than apredetermined temperature. The control portion 8 proceeds to Step S3 ina case where the temperature of the three-way catalyst is low and thecontrol portion 8 proceeds to Step S4 and starts the engine E and theheater heating treatment at the time of the initial engine operation isterminated in a case where the temperature of the three-way catalyst isnot low (in a case where the temperature of the three-way catalyst ishigh).

After the heating by the heater 37 is initiated in Step S3, the controlportion 8 proceeds to Step S4 and starts the engine E. After proceedingto Step S4, the control portion 8 terminates the heater heatingtreatment at the time of the initial engine operation.

In the control portion 8, the heating of the heater 37 is stopped whenthe heater heating treatment at the time of the initial engine operationis terminated. Here, the timing when the heating of the heater 37 isstopped may be when the three-way catalyst is completely warmed up, apredetermined time (approximately 20 seconds to approximately 30seconds) after the start of the engine, or the like.

Heater Heating Treatment at Time of Engine Restart

The heater heating treatment at a time of engine restart that isincluded in the engine control processing by the control portion 8 willbe described below with reference to FIG. 9. The heater heatingtreatment at the time of the engine restart is to initiate the heatingof the heater 37 in advance before the engine is restarted.

In Step S11, the control portion 8 determines whether or not the secondpredetermined condition (such as the temperature of the three-waycatalyst being low) has been satisfied. The control portion 8 proceedsto Step S12 in a case where the second predetermined condition issatisfied and the control portion 8 proceeds to Step S14 and starts theengine E and the heater heating treatment at the time of the enginerestart is terminated in a case where the second predetermined conditionis not satisfied.

In Step S12, the control portion 8 initiates the heating by the heater37. In Step S13, the control portion 8 determines whether or not thetemperature of the heater 37 is equal to or higher than a predeterminedtemperature. The control portion 8 proceeds to Step S14 in a case wherethe temperature of the heater 37 is equal to or higher than thepredetermined temperature and returns to Step S13 in a case where thetemperature of the heater 37 is lower than the predeterminedtemperature.

After the engine E is started in Step S14, the control portion 8terminates the heater heating treatment at the time of the enginerestart.

In the control portion 8, the heating of the heater 37 is stopped whenthe heater heating treatment at the time of the engine restart isterminated. Here, the timing when the heating of the heater 37 isstopped may be when the three-way catalyst is completely warmed up, apredetermined time (approximately 20 seconds to approximately 30seconds) after the restart of the engine, or the like.

Effects of Present Embodiment

The following effects can be obtained in the present embodiment.

As described above, in the present embodiment, the intake manifold 3 isprovided with the air intake apparatus main body portion 32, the portportion 33 provided integrally with the downstream side end portion ofthe air intake apparatus main body portion 32, and the heater 37. Theinjector 31 is disposed at a position where the fuel F can be injectedinto the heater 37. As a result, it is possible to prevent the fuel Ffrom intruding between at least the air intake apparatus main bodyportion 32 and the port portion 33 by integrally providing the airintake apparatus main body portion 32 and the port portion 33, and thusit is possible to make it difficult for the fuel F that has beeninjected from the injector 31 and adhered to the inner surface 3 a ofthe intake manifold 3 to intrude between the air intake apparatus mainbody portion 32 and the cylinder head 2. In addition, the fuel F thathas adhered without vaporization to the inner surface 3 a of the intakemanifold 3 can be vaporized by the heater 37. As a result, thevaporization of the fuel F by the heater 37 can be promoted andsealability can be ensured with respect to the fuel F injected from theinjector 31.

In addition, in the present embodiment, the heater 37 is disposed at thepart of the port portion 33 corresponding to the injection region 6 ofthe fuel F injected from the injector 31 as described above. As aresult, the fuel F that has adhered to the inner surface 3 a of theintake manifold 3 can be reliably vaporized by the heater 37 beingdisposed at the part of the port portion 33 that corresponds to theinjection region 6 of the fuel F. As a result, in the engine E, theair-fuel ratio in the combustion chamber 22 can be stabilized, and thusthe inside of the combustion chamber 22 is capable of being in an idealcombustion state and unburned exhaust gas can be reduced.

In addition, in the present embodiment, the heater 37 is provided on theinner surface 33 a side of the port portion 33 as described above. As aresult, the heater 37 can be provided at a position closer to the innersurface 3 a of the intake manifold 3 to which the fuel F adheres, andthus the fuel F that has adhered to the inner surface 3 a of the intakemanifold 3 can be sufficiently heated. As a result, the fuel F that hasadhered to the inner surface 3 a of the intake manifold 3 can bereliably vaporized.

In addition, in the present embodiment, the air intake apparatus mainbody portion 32 is provided with the flange portion 32 b providedintegrally with the end portion of the port portion 33 that is on theair intake apparatus main body portion 32 side as described above. Theintake manifold 3 is provided with the gasket 34. As a result, thegasket 34 may be disposed only between the flange portion 32 b of theair intake apparatus main body portion 32 and the outer surface 2 a ofthe cylinder head 2 unlike in a case where the air intake apparatus mainbody portion and the port portion are separate bodies and each of theair intake apparatus main body portion and the port portion is providedwith the flange portion, and thus the number of the gaskets 34 that arenecessary can be reduced. In addition, it is possible to suppress thefuel F intruding from the part between the port portion 33 and theflange portion 32 b by integrally providing the flange portion 32 b andthe end portion of the port portion 33 that is on the air intakeapparatus main body portion 32 side, and thus the amount by which thefuel F adheres to the gasket 34 can be reduced.

In addition, in the present embodiment, the gasket 34 is formed in acircumferential shape as described above. As a result, the opening 23 inthe upstream side end portion of the air intake port 21 in the intakeflow direction A can be surrounded by the gasket 34, and thus foreignmatter intrusion into the air intake port 21 can be suppressed.

In addition, in the present embodiment, the distal end portion 31 a ofthe injector 31 is disposed upstream of the boundary part D between theair intake apparatus main body portion 32 and the port portion 33 in theintake flow direction A as described above. As a result, a sufficientdistance can be ensured between the distal end portion 31 a of theinjector 31 and the combustion chamber 22, and thus the time for thefuel F injected from the injector 31 to flow into the combustion chamber22 can be sufficiently ensured. As a result, the vaporization of thefuel F injected from the injector 31 can be further promoted. Inaddition, since a sufficient distance can be ensured between the distalend portion 31 a of the injector 31 and the combustion chamber 22, it ispossible to suppress dirt adhesion to the injector 31 attributable to abackflow of the high-temperature gas in the combustion chamber 22 to theair intake port 21.

In addition, in the present embodiment, the air intake apparatus mainbody portion 32 is provided with the injector 31 as described above. Asa result, the part where the fuel F injected from the injector 31 hitsthe inner surface 3 a of the intake manifold 3 can be provided on theupstream side in the intake flow direction A as compared with a casewhere the cylinder head 2 is provided with the injector 31. At thistime, the heater 37 heating the fuel F introduced by the injector 31 isprovided on the upstream side in the intake flow direction A inaccordance with the position of disposition of the injector 31.Accordingly, the port portion 33 can be disposed at the upstream sidepart of the air intake port 21 in the intake flow direction A inaccordance with the positions of disposition of the injector 31 and theheater 37, and thus it is possible to reduce the amount of insertion ofthe port portion 33 into the air intake port 21. Here, it is possible tosuppress heat transfer from the cylinder head 2 to the air K in the airintake passage 35 at the part of the air intake port 21 where the portportion 33 is inserted by inserting the port portion 33 into the airintake port 21. As a result, it is possible to suppress a change in thestructure of the cylinder head 2 entailed by the insertion of the portportion 33 into the air intake port 21 (such as a change in water jacketdisposition) and a rise in the temperature of the air K in the airintake passage 35 can be suppressed.

In addition, in the present embodiment, the air intake apparatus mainbody portion 32 is provided with the injector 31 as described above. Asa result, it is possible not to provide the cylinder head 2 with athrough hole for attaching the injector 31 unlike in a case where thecylinder head 2 is provided with the injector 31. As a result, thecylinder head 2 can be reduced in size to the extent that the throughhole is not provided.

Modification Examples

The embodiment disclosed this time is illustrative and non-restrictivein all respects. The scope disclosed here is indicated not by thedescription of the embodiment but by the claims and includes everymodification (modification example) within the meanings and the scopesthat are equivalent to the claims.

For example, although the heater protection film 39 is a resin film inthe embodiment described above, the present invention is not limitedthereto. For example, the heater protection film may be made of anothermaterial insofar as the material has heat resistance, oil resistance,and chemical resistance. The heater protection film may be configured bythe heater being enclosed by the port portion and may be a metal tape.

In addition, although the port portion 33 is formed by the polyamide 6in the embodiment described above, the present invention is not limitedthereto. In the present invention, the port portion may be made ofanother material insofar as the material is a heat-resistant material.

In addition, although the heater protection film 39 is, for example, athin resin film having a thickness of approximately 0.125 [mm] in theembodiment described above, the present invention is not limitedthereto. For example, the thickness of the heater protection film may bedifferent from approximately 0.125 [mm].

In addition, although the heat insulating member 38 is formed by foammolding being performed on a polyamide in the embodiment describedabove, the present invention is not limited thereto. For example, theheat insulating member may have high heat insulating properties and maybe glass, melanin foam, Gore-Tex, cellulose, a special fiber, a platedresin material, or the like.

In addition, although the heater 37 has, for example, carbon graphite ora carbon nanotube as a heat generating element having carbon as a maincomponent in the embodiment described above, the present invention isnot limited thereto. In the present invention, the heater may be aceramic heater, a silicone rubber heater, a stainless steel heater, orthe like.

In addition, although a four-layer structure constitutes the internalstructure of the embedded recessed portion 36 part of the intakemanifold 3 in the embodiment described above, the present invention isnot limited thereto. For example, a three-layer structure may constitutethe internal structure of the part of an embedded recessed portion 236of an intake manifold 203 as in a first modification example illustratedin FIG. 10. In other words, not the embedded recessed portion but thethrough hole 236 penetrating a port portion 233 may be formed in theport portion 233 and a configuration in which each of the heaterprotection film 39, the heater 37, and a heat insulating member 238 isstacked in a surface contact state may be embedded in the through hole236. In addition, a five-layer structure may constitute the internalstructure of the embedded recessed portion part of an intake manifold303 as in a second modification example illustrated in FIG. 11. In otherwords, each of the heater protection film 39, the heater 37, a heaterprotection film 340, a heat insulating member 338, and a port portion333 may be stacked in a surface contact state in an embedded recessedportion 336 of the port portion 333.

In addition, although the control portion 8 is constituted by the ECUincluding the memory and the CPU in the embodiment described above, thepresent invention is not limited thereto. For example, the controlportion may be a dedicated control circuit controlling the temperatureof the heater other than the ECU.

In addition, although the control processing of the control portion 8has been described with a flow-driven flowchart in which the processingis performed in order along the processing flow for convenience ofdescription in the embodiment described above, the present invention isnot limited thereto. In the present invention, the control processing ofthe control portion may be performed by event-driven processing in whichthe processing is executed by event. In this case, the processing may beperformed by complete event-driven processing or by a combination ofevent-driven processing and flow-driven processing.

In addition, although the projecting distal end portion of the portportion 33 is disposed at the upstream side part of the reduced portion21 c of the air intake port 21 in the intake flow direction A in theembodiment described above, the present invention is not limitedthereto. In the present invention, the projecting distal end portion ofthe port portion may be disposed downstream of the middle position ofthe air intake port in the intake flow direction and the projectingdistal end portion of the port portion may be disposed upstream of themiddle position of the air intake port.

In addition, although the heater 37 is provided on the inner surface 33a side of the port portion 33 in the embodiment described above, thepresent invention is not limited thereto. In the present invention, theheater may be provided across the inner surface side of the port portionand the inner surface side of the air intake apparatus main bodyportion.

In addition, although the heater 37 is provided in the port portion 33in the embodiment described above, the present invention is not limitedthereto. In the present invention, the heater may be provided across theport portion and the downstream side end portion of the air intakeapparatus main body portion in the intake flow direction.

In addition, although a part of the boundary part D is disposed outsidethe outer surface of the cylinder block 1 in the Y direction in theembodiment described above, the present invention is not limitedthereto. For example, the entire boundary part may be disposed insidethe outer surface of the cylinder block in the Y direction.

In addition, although the upstream side end portion of the port portion33 and the downstream side end of the air intake apparatus main bodyportion 32 are integrally provided over the entire circumferentialdirection around the central axis line that extends in the intake flowdirection A in the embodiment described above, the present invention isnot limited thereto. For example, a part of the upstream side endportion of the port portion and a part of the downstream side endportion of the air intake apparatus main body portion may be integrallyprovided so as to correspond to the heater disposition part around thecentral axis line that extends in the intake flow direction.

In addition, although the layered structure formed by the heaterprotection film 39, the heater 37, the heat insulating member 38, andthe intake manifold 3 is formed at a part of the intake manifold 3 inthe embodiment described above, the present invention is not limitedthereto. For example, a layered structure formed by the heaterprotection film, the heater, and the intake manifold may be formed at apart of the intake manifold.

In addition, although the predetermined angle θ of the injector 31 is anangle at which a part of the heater 37 can be disposed and a part of theair intake port 24 can be disposed within the range of the downstreamend of the injection region 6 in the embodiment described above, thepresent invention is not limited thereto. For example, the predeterminedangle of the injector may be an angle at which only a part of the heatercan be disposed within the range of the downstream end of the injectionregion.

In addition, although the heater 37 is provided in the vicinity of thedistal end portion of the intake manifold 3 in the embodiment describedabove, the present invention is not limited thereto. For example, theheater may be provided upstream of the vicinity of the distal endportion of the intake manifold in the intake flow direction.

An air intake apparatus for an internal combustion engine according toan aspect of this disclosure includes an air intake apparatus main bodyportion introducing air into a cylinder, a port portion providedintegrally with a downstream side end portion of the air intakeapparatus main body portion and inserted into an air intake port in acylinder head, an air intake passage formed inside the air intakeapparatus main body portion and the port portion, and through which anair-fuel mixture containing air and fuel flows, an injector provided inthe air intake apparatus main body portion and introducing fuel into theair intake passage, and a heater heating the fuel introduced by theinjector. The injector is disposed at a position where the fuel iscapable of being injected into the heater.

In the air intake apparatus for an internal combustion engine accordingto the aspect of this disclosure, the air intake apparatus main bodyportion, the port portion provided integrally with the downstream sideend portion of the air intake apparatus main body portion, and theheater are provided as described above. The injector is disposed at aposition where the fuel can be injected into the heater. As a result, itis possible to prevent the fuel from intruding between at least the airintake apparatus main body and the port portion by integrally providingthe air intake apparatus main body portion and the port portion, andthus it is possible to make it difficult for the fuel that has beeninjected from the injector and adhered to the inner surface of the airintake apparatus to intrude between the air intake apparatus main bodyportion and the cylinder head. In addition, the fuel that has adheredwithout vaporization to the inner surface of the air intake apparatuscan be vaporized by the heater. As a result, the vaporization of thefuel by the heater can be promoted and sealability can be ensured withrespect to the fuel injected from the injector.

In the air intake apparatus for an internal combustion engine accordingto the aspect described above, it is preferable that at least a part ofthe heater is disposed at a part of the port portion corresponding to aninjection region of the fuel injected from the injector.

With this configuration, the fuel that has adhered to the inner surfaceof the air intake apparatus can be reliably vaporized by at least a partof the heater being disposed at the part of the port portion thatcorresponds to the injection region of the fuel. As a result, in theinternal combustion engine, the air-fuel ratio in a combustion chambercan be stabilized, and thus the inside of the combustion chamber iscapable of being in an ideal combustion state and unburned exhaust gascan be reduced.

In the air intake apparatus for an internal combustion engine accordingto the aspect described above, it is preferable that at least a part ofthe heater is provided on an inner surface side of the port portion.

With this configuration, the heater can be provided at a position closerto the inner surface of the air intake apparatus to which the fueladheres, and thus the fuel that has adhered to the inner surface of theair intake apparatus can be sufficiently heated. As a result, the fuelthat has adhered to the inner surface of the air intake apparatus can bereliably vaporized.

In the air intake apparatus for an internal combustion engine accordingto the aspect described above, it is preferable that the air intakeapparatus main body portion includes a flange portion disposed so as toface an outer surface of the cylinder head around an opening in anupstream side end portion of the air intake port and provided integrallywith an end portion of the port portion on the air intake apparatus mainbody portion side, and the air intake apparatus further includes a sealmember disposed between the flange portion and the outer surface of thecylinder head.

With this configuration, the seal member may be disposed only betweenthe flange portion of the air intake apparatus main body portion and theouter surface of the cylinder head unlike in a case where the air intakeapparatus main body portion and the port portion are separate bodies andeach of the air intake apparatus main body portion and the port portionis provided with the flange portion, and thus the number of the sealmembers that are necessary can be reduced. In addition, it is possibleto suppress the fuel intruding from the part between the port portionand the flange portion by integrally providing the flange portion andthe end portion of the port portion that is on the air intake apparatusmain body portion side, and thus the amount by which the fuel adheres tothe seal member can be reduced.

In this case, it is preferable that the seal member is formed in acircumferential shape.

With this configuration, the opening in the upstream side end portion ofthe air intake port in an intake flow direction can be surrounded by theseal member, and thus foreign matter intrusion into the air intake portcan be suppressed.

In the air intake apparatus for an internal combustion engine accordingto the aspect described above, it is preferable that a distal endportion of the injector is disposed upstream of a boundary part betweenthe air intake apparatus main body portion and the port portion in anintake flow direction.

With this configuration, a sufficient distance can be ensured betweenthe distal end portion of the injector and the combustion chamber, andthus the time for the fuel injected from the injector to flow into thecombustion chamber can be sufficiently ensured. As a result, thevaporization of the fuel injected from the injector can be furtherpromoted. In addition, since a sufficient distance can be ensuredbetween the distal end portion of the injector and the combustionchamber, it is possible to suppress dirt adhesion to the injectorattributable to a backflow of the high-temperature gas in the combustionchamber to the air intake port.

The following configuration is also conceivable in the air intakeapparatus for an internal combustion engine according to the aspectdescribed above.

APPENDIX 1

The air intake apparatus for an internal combustion engine according tothe aspect described above further includes a recessed portion recessedoutward in a direction orthogonal to the intake flow direction in atleast an inner surface of the port portion and the heater is disposed inthe recessed portion.

With this configuration, the intake air that flows through the airintake passage does not directly hit the heater by the heater beingdisposed in the recessed portion of the port portion, and thus a declinein heater temperature attributable to the intake air that flows throughthe air intake passage can be suppressed.

APPENDIX 2

In the recessed portion, a heat insulating member is disposed at anouter side and the heater is stacked inside the heat insulating memberin the direction orthogonal to the intake flow direction.

With this configuration, the heat insulating member is capable ofsuppressing transfer of the heat generated in the heater to the portportion during the heating of the heater, and thus it is possible tosuppress escaping of the heat of the heater to a place other than adesired heating location. As a result, the heat generated in the heatercan be efficiently and easily transmitted to the fuel that has adheredto the inner surface of the air intake apparatus, and thus the fuel canbe efficiently vaporized.

APPENDIX 3

In the air intake apparatus for an internal combustion engine accordingto the aspect described above, the air intake apparatus main bodyportion and the port portion are provided at each of a plurality of theair intake ports respectively supplying the air-fuel mixture to aplurality of the cylinders in the internal combustion engine.

With this configuration, the vaporization of the fuel by the heater canbe promoted in each cylinder and sealability can be ensured with respectto the fuel injected from the injector even in the case of amulti-cylinder internal combustion engine.

APPENDIX 4

In the air intake apparatus for an internal combustion engine accordingto the aspect described above, an air insulation layer is providedbetween an outer surface of the port portion and an inner surface of theair intake port in a direction orthogonal to the intake flow direction.

With this configuration, it is possible to suppress heat transfer fromthe cylinder head to the port portion even when the temperature of thecylinder head has risen to a high temperature, and thus it is possibleto suppress a rise in the temperature of the intake air in the airintake passage.

The principles, preferred embodiment and mode of operation of thepresent invention have been described in the foregoing specification.However, the invention which is intended to be protected is not to beconstrued as limited to the particular embodiments disclosed. Further,the embodiments described herein are to be regarded as illustrativerather than restrictive. Variations and changes may be made by others,and equivalents employed, without departing from the spirit of thepresent invention. Accordingly, it is expressly intended that all suchvariations, changes and equivalents which fall within the spirit andscope of the present invention as defined in the claims, be embracedthereby.

What is claimed is:
 1. An air intake apparatus for an internalcombustion engine, the air intake apparatus comprising: an air intakeapparatus main body portion introducing air into a cylinder; a portportion provided integrally with a downstream side end portion of theair intake apparatus main body portion and inserted into an air intakeport in a cylinder head; an air intake passage formed inside the airintake apparatus main body portion and the port portion, and throughwhich an air-fuel mixture containing air and fuel flows; an injectorprovided in the air intake apparatus main body portion and introducingthe fuel into the air intake passage; and a heater heating the fuelintroduced by the injector, wherein the injector is disposed at aposition where the fuel is capable of being injected into the heater. 2.The air intake apparatus for an internal combustion engine according toclaim 1, wherein at least a part of the heater is disposed at a part ofthe port portion corresponding to an injection region of the fuelinjected from the injector.
 3. The air intake apparatus for an internalcombustion engine according to claim 1, wherein at least a part of theheater is provided on an inner surface side of the port portion.
 4. Theair intake apparatus for an internal combustion engine according toclaim 1, wherein the air intake apparatus main body portion includes aflange portion disposed so as to face an outer surface of the cylinderhead around an opening in an upstream side end portion of the air intakeport and provided integrally with an end portion of the port portion onthe air intake apparatus main body portion side, and the air intakeapparatus further comprises a seal member disposed between the flangeportion and the outer surface of the cylinder head.
 5. The air intakeapparatus for an internal combustion engine according to claim 4,wherein the seal member is formed in a circumferential shape.
 6. The airintake apparatus for an internal combustion engine according to claim 1,wherein a distal end portion of the injector is disposed upstream of aboundary part between the air intake apparatus main body portion and theport portion in an intake flow direction.
 7. The air intake apparatusfor an internal combustion engine according to claim 1, furthercomprising a recessed portion recessed outward in a direction orthogonalto an intake flow direction in at least an inner surface of the portportion, wherein the heater is disposed in the recessed portion.
 8. Theair intake apparatus for an internal combustion engine according toclaim 7, wherein in the recessed portion a heat insulating member isdisposed at an outer side and the heater is stacked inside the heatinsulating member in the direction orthogonal to the intake flowdirection.
 9. The air intake apparatus for an internal combustion engineaccording to claim 1, wherein the air intake apparatus main body portionand the port portion are provided at each of a plurality of the airintake ports respectively supplying the air-fuel mixture to a pluralityof the cylinders in the internal combustion engine.
 10. The air intakeapparatus for an internal combustion engine according to claim 1,wherein an air insulation layer is provided between an outer surface ofthe port portion and an inner surface of the air intake port in adirection orthogonal to an intake flow direction.